Add --format option

README.md

@@ -488,6 +488,35 @@ def autocorrect(_processed_source, offense)
 end
 ```
 
+## Output formats
+
+You can change the output format of ERB Lint by specifying formatters with the `-f/--format` option.
+
+### Multiline (default)
+
+```sh
+$ erblint
+Linting 8 files with 12 linters...
+
+Remove multiple trailing newline at the end of the file.
+In file: app/views/users/show.html.erb:95
+
+Remove newline before `%>` to match start of tag.
+In file: app/views/subscriptions/index.html.erb:38
+
+2 error(s) were found in ERB files
+```
+
+### Compact
+
+```sh
+erblint --format compact
+Linting 8 files with 12 linters...
+app/views/users/show.html.erb:95:0: Remove multiple trailing newline at the end of the file.
+app/views/users/_graph.html.erb:27:37: Extra space detected where there should be no space
+2 error(s) were found in ERB files
+```
+
 ## License
 
 This project is released under the [MIT license](LICENSE.txt).

lib/erb_lint.rb

@@ -10,8 +10,15 @@
 require 'erb_lint/runner_config'
 require 'erb_lint/runner'
 require 'erb_lint/version'
+require 'erb_lint/stats'
+require 'erb_lint/reporter'
 
 # Load linters
 Dir[File.expand_path('erb_lint/linters/**/*.rb', File.dirname(__FILE__))].each do |file|
   require file
 end
+
+# Load reporters
+Dir[File.expand_path('erb_lint/reporters/**/*.rb', File.dirname(__FILE__))].each do |file|
+  require file
+end

lib/erb_lint/cli.rb

@@ -16,15 +16,6 @@ class CLI
     class ExitWithFailure < RuntimeError; end
     class ExitWithSuccess < RuntimeError; end
 
-    class Stats
-      attr_accessor :found, :corrected, :exceptions
-      def initialize
-        @found = 0
-        @corrected = 0
-        @exceptions = 0
-      end
-    end
-
     def initialize
       @options = {}
       @config = nil
@@ -51,9 +42,12 @@ def run(args = ARGV)
         failure!('no linter available with current configuration')
       end
 
-      puts "Linting #{lint_files.size} files with "\
-        "#{enabled_linter_classes.size} #{'autocorrectable ' if autocorrect?}linters..."
-      puts
+      @options[:format] ||= :multiline
+      @stats.files = lint_files.size
+      @stats.linters = enabled_linter_classes.size
+
+      reporter = Reporter.create_reporter(@options[:format], @stats, autocorrect?)
+      reporter.preview
 
       runner = ERBLint::Runner.new(file_loader, @config)
 
@@ -72,20 +66,7 @@ def run(args = ARGV)
         end
       end
 
-      if @stats.corrected > 0
-        corrected_found_diff = @stats.found - @stats.corrected
-        if corrected_found_diff > 0
-          warn(Rainbow(
-            "#{@stats.corrected} error(s) corrected and #{corrected_found_diff} error(s) remaining in ERB files"
-          ).red)
-        else
-          puts Rainbow("#{@stats.corrected} error(s) corrected in ERB files").green
-        end
-      elsif @stats.found > 0
-        warn(Rainbow("#{@stats.found} error(s) were found in ERB files").red)
-      else
-        puts Rainbow("No errors were found in ERB files").green
-      end
+      reporter.show
 
       @stats.found == 0 && @stats.exceptions == 0
     rescue OptionParser::InvalidOption, OptionParser::InvalidArgument, ExitWithFailure => e
@@ -126,15 +107,12 @@ def run_with_corrections(runner, filename)
         file_content = corrector.corrected_content
         runner.clear_offenses
       end
+      offenses_filename = relative_filename(filename)
+      offenses = runner.offenses || []
 
-      @stats.found += runner.offenses.size
-      runner.offenses.each do |offense|
-        puts <<~EOF
-          #{offense.message}#{Rainbow(' (not autocorrected)').red if autocorrect?}
-          In file: #{relative_filename(filename)}:#{offense.line_range.begin}
-
-        EOF
-      end
+      @stats.found += offenses.size
+      @stats.processed_files[offenses_filename] ||= []
+      @stats.processed_files[offenses_filename] |= offenses
     end
 
     def correct(processed_source, offenses)
@@ -258,6 +236,15 @@ def option_parser
           end
         end
 
+        opts.on("--format FORMAT", format_options_help) do |format|
+          unless Reporter.available_format?(format)
+            error_message = invalid_format_error_message(format)
+            failure!(error_message)
+          end
+
+          @options[:format] = format
+        end
+
         opts.on("--lint-all", "Lint all files matching configured glob [default: #{DEFAULT_LINT_ALL_GLOB}]") do |config|
           @options[:lint_all] = config
         end
@@ -289,5 +276,15 @@ def option_parser
         end
       end
     end
+
+    def format_options_help
+      "Report offenses in the given format: "\
+      "(#{Reporter.available_formats.join(', ')}) (default: multiline)"
+    end
+
+    def invalid_format_error_message(given_format)
+      formats = Reporter.available_formats.map { |format| "  - #{format}\n" }
+      "#{given_format}: is not a valid format. Available formats:\n#{formats.join}"
+    end
   end
 end

lib/erb_lint/offense.rb

@@ -31,5 +31,13 @@ def ==(other)
     def line_range
       Range.new(source_range.line, source_range.last_line)
     end
+
+    def line_number
+      line_range.begin
+    end
+
+    def column
+      source_range.column
+    end
   end
 end

lib/erb_lint/reporter.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+require 'active_support/core_ext/class'
+
+module ERBLint
+  class Reporter
+    def self.create_reporter(format, *args)
+      reporter_klass = "#{ERBLint::Reporters}::#{format.to_s.camelize}Reporter".constantize
+      reporter_klass.new(*args)
+    end
+
+    def self.available_format?(format)
+      available_formats.include?(format.to_s)
+    end
+
+    def self.available_formats
+      descendants
+        .map(&:to_s)
+        .map(&:demodulize)
+        .map(&:underscore)
+        .map { |klass_name| klass_name.sub("_reporter", "") }
+        .sort
+    end
+
+    def initialize(stats, autocorrect)
+      @stats = stats
+      @autocorrect = autocorrect
+    end
+
+    def preview; end
+
+    def show; end
+
+    private
+
+    attr_reader :stats, :autocorrect
+    delegate :processed_files, to: :stats
+  end
+end

lib/erb_lint/reporters/compact_reporter.rb

@@ -0,0 +1,60 @@
+# frozen_string_literal: true
+
+module ERBLint
+  module Reporters
+    class CompactReporter < Reporter
+      def preview
+        puts "Linting #{stats.files} files with "\
+          "#{stats.linters} #{'autocorrectable ' if autocorrect}linters..."
+      end
+
+      def show
+        processed_files.each do |filename, offenses|
+          offenses.each do |offense|
+            puts format_offense(filename, offense)
+          end
+        end
+
+        footer
+        summary
+      end
+
+      private
+
+      def format_offense(filename, offense)
+        [
+          "#{filename}:",
+          "#{offense.line_number}:",
+          "#{offense.column}: ",
+          offense.message.to_s,
+        ].join
+      end
+
+      def footer; end
+
+      def summary
+        if stats.corrected > 0
+          report_corrected_offenses
+        elsif stats.found > 0
+          warn(Rainbow("#{stats.found} error(s) were found in ERB files").red)
+        else
+          puts Rainbow("No errors were found in ERB files").green
+        end
+      end
+
+      def report_corrected_offenses
+        corrected_found_diff = stats.found - stats.corrected
+
+        if corrected_found_diff > 0
+          message = Rainbow(
+            "#{stats.corrected} error(s) corrected and #{corrected_found_diff} error(s) remaining in ERB files"
+          ).red
+
+          warn(message)
+        else
+          puts Rainbow("#{stats.corrected} error(s) corrected in ERB files").green
+        end
+      end
+    end
+  end
+end

lib/erb_lint/reporters/multiline_reporter.rb

@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+require_relative "compact_reporter"
+
+module ERBLint
+  module Reporters
+    class MultilineReporter < CompactReporter
+      private
+
+      def format_offense(filename, offense)
+        <<~EOF
+
+          #{offense.message}#{Rainbow(' (not autocorrected)').red if autocorrect}
+          In file: #{filename}:#{offense.line_number}
+        EOF
+      end
+
+      def footer
+        puts
+      end
+    end
+  end
+end

lib/erb_lint/stats.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+module ERBLint
+  class Stats
+    attr_accessor :found,
+                  :corrected,
+                  :exceptions,
+                  :linters,
+                  :files,
+                  :processed_files
+
+    def initialize(
+      found: 0,
+      corrected: 0,
+      exceptions: 0,
+      linters: 0,
+      files: 0,
+      processed_files: {}
+    )
+      @found = found
+      @corrected = corrected
+      @exceptions = exceptions
+      @linters = linters
+      @files = files
+      @processed_files = processed_files
+    end
+  end
+end